"Our study shows that for inactive teenagers, emphasizing the emotional benefits of exercise may be a more effective way to encourage exercise than highlighting traditional health benefits," study co-author Reema Sirriyeh, of the University of Leeds in England, said in a statement from the British Psychological Society.

The study examined the value of sending daily text messages about exercise to 128 students aged 16 to 19 at four schools in West Yorkshire. The teens received the messages for two weeks.

Some students received messages that made exercise sound enjoyable, such as "Physical activity can make you feel cheerful," while others got messages highlighting health benefits, such as "Physical activity can keep your heart healthy." A third group received both types of messages, the study authors noted.

The researchers found that the level of activity among all the teens grew by an average of 31.5 minutes of moderate activity per week after receiving the messages for two weeks. Inactive teens who received the messages geared toward the emotional benefits of exercise boosted their levels of activity by two hours per week.

"Statistics from the British Heart Foundation show that from the age of 16, girls' levels of physical activity begin to decrease," Sirriyeh noted. "As patterns of behavior that start in the teenage years tend to persist into adulthood, it's vitally important that teenagers get into healthy patterns, like taking regular exercise."

The findings were published online Feb. 17 in the British Journal of Health Psychology.

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SOURCE: British Psychological Society, news release, Feb. 17, 2010

-- Randy Dotinga